Table 1.

Basic characteristics of the study populations from the three cohorts

Harvard cohort (discovery)MD Anderson cohort (replication)Nanjing cohort (replication)
Early stageLate stageEarly stageLate stageLate stage
Total452526241547609
Age
 Mean ± SD67.86 ± 9.6663.47 ± 10.8765.43 ± 9.8560.23 ± 10.5160.19 ± 10.38
Sex
 Male214 (47.35%)259 (49.24%)122 (50.62)331 (60.51)439 (72.09)
 Female238 (52.65%)267 (50.76%)119 (49.38)216 (39.49)170 (27.91)
Smoking status
 Never40 (8.85%)52 (9.89%)00232 (38.10)
 Former238 (52.65%)260 (49.43%)141 (58.51)271 (49.54)73 (11.99)
 Current174 (38.50%)214 (40.68%)100 (41.49)276 (50.46)304 (49.91)
Histology
 Adeno199 (44.03%)285 (54.18%)119 (49.38)275 (50.27)395 (64.86)
 SQC135 (29.87%)79 (15.02%)74 (30.71)147 (26.87)214 (35.14)
 Others118 (26.11%)162 (30.80%)48 (19.92)125 (22.85)0
Stage
 I381 (84.29%)176 (73.03%)
 II71 (15.71%)65 (27.97%)
 III238 (45.25%)302 (55.21%)376 (61.74)
 IV288 (54.75%)245 (44.79%)233 (38.26)

Abbreviations: adeno, adenocarcinoma; SQC, squamous carcinoma.